Guest Anonymous Posted April 20, 2002 Share Posted April 20, 2002 Hi all I have a 72 240z with a l28, headers 2 1/2 pipe, mallory unilite ignition, holley 450 on a Bob sharp racing intake, still have a pair of 72 SU's lying around somewhere that I might use. I have a n42 head that has been ported and polished and shaved .03 or .04 not sure ( anyways I was just wanting to know do I need to shim the cam towers or get a thicker head gasket with this head? Have a p79 on it atm and it has flatop pistons. Any help would be great, Thx Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted April 20, 2002 Share Posted April 20, 2002 First Questoin(!)...welcome to the site Altar. I'm not an expert on the inline (even tho I'm still an Inliner); however, from all Chevy, Ford, Mopar books I've read on their V8's, they claim the Cylinder Head Gasket is good for absorbing up to .027" of an inch. The real question would be, "Do you know the past history of your cylinder head/has it been milled before?" If it has, this would beg the question, "How Much?" The best thing for you to do is to find a local Nissan Dealer (they should know-or know someone in their neighborhood that does know) what the actual thickness of your cylinder head would be if never milled. Once you know what the actual thickness of the cylinder head is and where to take your measurments then you can take your own measurements & deduct that from the original thickness. Possibly someone else might jump in here who has dabbled in the Inliner Cylinder Head world. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 20, 2002 Share Posted April 20, 2002 The first time I saw the head was about 5 years ago in a speed shop close to my house. He wanted like $600 for it, someone had alot of work done on it and couldn't pay the bill. I went back there a week ago and he still had it ). It didn't look all shinny and new like before so I offered him a $100 for it and he took it. He said it had never been worked on before till he got it. Asked him how much it was shaved and he said .03 or .04 I have heard that you could double up on the head gaskets instead of shimming the cam towers,any draw backs with this setup? Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted April 20, 2002 Share Posted April 20, 2002 I'm not sure you would have to shim the towers...but if you do, well, it shouldn't be too tough to do since the head is not on the engine yet. Where in Fla are you located? mike Quote Link to comment Share on other sites More sharing options...
katman Posted April 23, 2002 Share Posted April 23, 2002 Stock thickness on all the L heads would be 4.248 (107.9 mm), although most measure a little thicker, like 4.252 unmolested. Knowing that you can figure how much has been shaved off. Up to 0.030 I wouldn't bother shimming- it likely will hose up your rocker geometry enough to need different lash pads, just adjust the cam timing with the sprocket and take up the slack with the curved chain guide. At 0.040 you might consider a 2mm HKS gasket, which is 0.079 thick as opposed to stock 0.052. However it is designed for the big bore kit and has huge holes (90mm I think). There's also a "head saver" soft copper gasket that's 0.020 from Fel-Pro which you add to a stock gasket. Best of luck. Quote Link to comment Share on other sites More sharing options...
DAW Posted April 23, 2002 Share Posted April 23, 2002 Katman is right re measuring the head to know how much is gone. The dimension is from the head surface to the valve cover mounting surface. The chain tensioner can't take up slack between the crank gear and cam gear because that side is always pulling the cam gear. Rotating the gear through adjustment won't increase the lost distance in length (i.e. raise the cam) and the change in geometry between the two gear centers. It's not the same as a stretched chain. So if it's a big cut, you'll need to use shims..but take a close look and make sure that shims aren't already installed. Calculate the c.r. before you but a $100 2mm head gasket that's for a 90mm bore (stock L28 is 86mm). If you determine how big a shave the head's had, people on this site can help calculate the change in combustion chamber volume. DAW Quote Link to comment Share on other sites More sharing options...
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